I have a dell inspiron 8000 laptop. the battery only lasts 35mins. it has a
li-on 8 cell battery which should last about 2-3 hours. the battery has a built in tester . when u press it all 5 leds light up. that indicates the battery is o.k . .therefore is it the battery or is the laptop draining the battery . any advice or help would be gratefully rcieved.:

Go into the bios and see if their is an option to change the power settings, the computer might be set to use as much power as it can to keep its performance up, but if u set it to lower it will try and conserve the battery power and use less but u will notice a great change in the speed of your system.

thanks for the replies guys. i have checked the bios settings and they are set to the minimum whilst using the battery. the problem is that when fully charged i.e 100% it will display 90% after 25 mins then 5% 5 mins later.
i suspect the baTTery is faulty, yet when i press the test button on the battery all the l.e.d.s light up. (all 5). what i dont wanna do is spend 60quid on a new battery and have the same problem as b4.